Display device and manufacturing method thereof

ABSTRACT

A display device includes a substrate, a first electrode disposed on the substrate, a second electrode disposed on the substrate and spaced apart from the first electrode, a plurality of first protruding electrodes disposed on the first electrode, a plurality of second protruding electrodes disposed on the second electrode, and a plurality of light emitting elements electrically connected to the plurality of first protruding electrodes and the plurality of second protruding electrodes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application claims priority under 35U.S.C. § 119 of Korean Patent Application No. 10-2018-0135435, filed onNov. 6, 2018, the disclosure of which is hereby incorporated byreference in its entirety.

BACKGROUND

The present disclosure relates to a display device and a method ofmanufacturing the same, and more particularly, to a display devicecapable of improving an alignment degree of light emitting elements anda method of manufacturing the same.

Generally, a display device includes a plurality of pixels fordisplaying an image. There are various types of pixels such as a pixelincluding a liquid crystal layer, a pixel including an electrowettinglayer, a pixel including an electrophoretic layer, and a pixel includinga light emitting element. Among them, a display device including aself-light light emitting element does not require a separate lightsource.

Recently, as a light emitting element, a microscale light emitting diode(LED) element is under development. The microscale LED element may bemanufactured in nano or micro units and has a rod-like or bar-likeshape. The microscale LED elements may be horizontally arranged andelectrically connected to a first electrode and a second electrodehaving opposite polarities.

Voltages of the opposite polarities are applied to the first electrodeand the second electrode, and a plurality of microscale LED elements arealigned toward the first electrode and the second electrode by anelectric field formed between the first electrode and the secondelectrode. However, when a plurality of microscale LED elements isprovided for the first electrode and the second electrode, themicroscale LED elements may not be uniformly aligned.

SUMMARY

The present disclosure provides a display device capable of improving analignment degree of light emitting elements and a method ofmanufacturing the same.

An embodiment of the inventive concept provides a display deviceincluding: a substrate; a first electrode disposed on the substrate; asecond electrode disposed on the substrate and spaced apart from thefirst electrode; a plurality of first protruding electrodes disposed onthe first electrode; a plurality of second protruding electrodesdisposed on the second electrode; and a plurality of light emittingelements electrically connected to the plurality of first protrudingelectrodes and the plurality of second protruding electrodes.

In an embodiment of the inventive concept, a manufacturing method of adisplay device includes: providing a first conductive material on asubstrate; providing a second conductive material on the firstconductive material; providing a first photoresist pattern including afirst portion on the second conductive material and a plurality ofsecond portions spaced apart from each other and disposed on the firstportion; removing portions of the first and second conductive materialsthat are exposed by the first photoresist pattern to form a firstelectrode and a second electrode defined by remaining portions of thefirst conductive material; removing the first photoresist pattern froman upper portion of the first photoresist pattern by a thickness of thefirst portion to form a second photoresist pattern; removing portions ofthe second conductive material that are exposed by the secondphotoresist pattern to form a plurality of first protruding electrodesand a plurality of second protruding electrodes; and electricallyconnecting a plurality of light emitting elements to the plurality offirst protruding electrodes and the plurality of second protrudingelectrodes.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings are included to provide a furtherunderstanding of the inventive concept, and are incorporated in andconstitute a part of the present specification. The drawings illustrateexemplary embodiments of the inventive concept and, together with thedescription, serve to explain principles of the inventive concept. Inthe drawings:

FIG. 1 is a plan view of a display device according to an embodiment ofthe inventive concept;

FIG. 2 is an equivalent circuit diagram of a pixel shown in FIG. 1;

FIG. 3 is a plan view illustrating the pixel shown in FIG. 2 including afirst electrode and a second electrode that are connected to the lightemitting element;

FIG. 4 is a perspective view of one light emitting element shown in FIG.3;

FIG. 5 is a cross-sectional view taken along a line I-I′ of FIG. 3;

FIG. 6 is a cross-sectional view taken along a line II-II′ of FIG. 3;and

FIGS. 7 to 14 are views for showing a manufacturing method of a displaydevice according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

In the present specification, a component (or an area, a layer, a part,etc.) that is referred to as being “on”, “connected to,” or “combinedto” another component means that the component may be directly on,connected to, or combined to the other component, or a third componenttherebetween may be present.

Like reference numerals refer to like elements. Additionally, in thedrawings, the thicknesses, proportions, and dimensions of components areexaggerated for the convenience of description.

The term “and/or” includes all of one or more combinations defined bylisted components.

It will be understood that the terms “first” and “second” are usedherein to describe various components, but these components should notbe limited by these terms. The above terms are used only to distinguishone component from another. For example, a first component may bereferred to as a second component and vice versa without departing fromthe scope of the inventive concept. The singular expressions includeplural expressions unless the context clearly dictates otherwise.

In addition, terms such as “below,” “lower,” “on,” and “upper” are usedto describe a relationship of configurations shown in the drawing. Theseterms are described as a relative concept based on an orientation shownin the drawing. For example, “below” may become “on,” and “on” become“below” if the orientation of the drawing is switched upside down ordownside up.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as terms commonly understood bythose skilled in the art to which the present disclosure pertains. Inaddition, terms such as terms defined in commonly used dictionariesshould be interpreted as having a meaning that is consistent withmeaning in the context of the related art, and unless the term isinterpreted in an ideal or overly formal sense, they may be explicitlydefined herein.

In various embodiments of the inventive concept, the term “include,”“comprise,” “including,” or “comprising” specifies a property, a region,a fixed number, a step, a process, an element, and/or a component butdoes not exclude other properties, regions, fixed numbers, steps,processes, elements, and/or components.

Hereinafter, exemplary embodiments of the inventive concept aredescribed in more detail with reference to the accompanying drawings.

FIG. 1 is a plan view of a display device according to an embodiment ofthe inventive concept.

Referring to FIG. 1, a display device DD according to an embodiment ofthe present disclosure may include a display panel DP, a scan driverSDV, and a data driver DDV. The scan driver SDV and the data driver DDVmay be disposed on the display panel DP.

The display panel DP may have a rectangular shape having short sides ina first direction DR1 and long sides in a second direction DR2 thatintersects the first direction DR1. However, the present disclosure isnot limited to this, and the display panel DP may have various shapessuch as a circular shape and a polygonal shape.

The display panel DP may include a display area DA and a non-displayarea NDA that surrounds the display area DA. The display area DA maycorrespond to an area for displaying an image, and the non-display areaNDA may correspond to an area that does not display an image.

The display panel DP may include a plurality of pixels PX, a pluralityof scan lines SL1 to SLm, and a plurality of data lines DL1 to DLn,where m and n are natural numbers. Illustratively, the pixels PX may bearranged in a matrix form, but the arrangement form of the pixels PX isnot limited thereto.

The pixels PX may be disposed in the display area DA and connected tothe scan lines SL1 to SLm and the data lines DL1 to DLn. Each of thepixels PX may include a light emitting element for displaying an image.

The scan driver SDV and the data driver DDV may be disposed in thenon-display area NDA. The scan driver SDV may be disposed in thenon-display area NDA adjacent to one of the long sides of the displaypanel DP. The data driver DDV may be disposed in the non-display areaNDA adjacent to one of the short sides of the display panel DP.

The scan lines SL1 to SLm may extend in the first direction DR1 and maybe connected to the scan driver SDV. The data lines DL1 to DLn mayextend in the second direction DR2 and may be connected to the datadriver DDV.

The scan driver SDV generates a plurality of scan signals, and the scansignals may be applied to the pixels PX through the scan lines SL1 toSLm. The scan signals may be sequentially applied to the pixels PX. Thedata driver DDV generates a plurality of data voltages, and the datavoltages may be applied to the pixels PX through the data lines DL1 toDLn.

Although not shown in the drawings, the display device DD may include atiming controller for controlling the operation of the scan driver SDVand the data driver DDV. For example, the timing controller may generatea scan control signal and a data control signal in response toexternally received control signals. The timing controller may alsoreceive image signals externally, and convert the data format of theimage signals to match the interface specification with the data driverDDV, and provide the converted image signals to the data driver DDV. Itis noted that the data format of the externally received image signalsmay not need to be converted if the image signals comply with theinterface specification with the data driver DDV.

The scan driver SDV may generate scan signals in response to the scancontrol signal. The data driver DDV may receive the image signals fromthe timing controller and may generate the data voltages correspondingto the image signals in response to the data control signal.

The pixels PX may be provided with the data voltages through the datalines DL1 to DLn in response to the scan signals that are receivedthrough scan lines SL1 to SLm. The pixels PX can display an image byemitting light of a luminance corresponding to the data voltages.

FIG. 2 is an equivalent circuit diagram of a pixel shown in FIG. 1.

Although FIG. 2 shows an equivalent circuit diagram of one pixel PX ofthe pixels PX shown in FIG. 1, other pixels PX shown in FIG. 1 may havethe same equivalent circuit diagram as the pixel PX shown in FIG. 2.Illustratively, a pixel PX connected to the scan line SLi and the dataline DLj is shown in FIG. 2, where i and j are natural numbers equal toand greater than 1 and equal to or less than m and n, respectively.

Referring to FIG. 2, the pixel PX may include a light emitting elementED (e.g., a light emitting diode), a driving element DT (e.g., a drivingtransistor), a capacitance element C (e.g., a capacitor), and aswitching element ST (e.g., a switching transistor). The light emittingelement ED may collectively represent a plurality of light emittingelements ED included in the pixel PX. A plurality of light emittingelements ED included in the pixel PX will be shown in FIG. 3 below.

According to one embodiment, the driving element DT and the switchingelement ST may be P-type transistors. However, the present disclosure isnot limited thereto, and the driving element DT and the switchingelement ST may be N-type transistors. The capacitance element C may be acapacitor.

The driving element DT includes an input terminal connected to a firstcap electrode of the capacitance element C and a first power supply linePL1, an output terminal connected to the light emitting element ED, anda control terminal connected to an output terminal of the switchingelement ST. The driving element DT may receive a first power supplyvoltage ELVDD through the first power supply line PL1. A second capelectrode of the capacitance element C may be connected to the controlterminal of the driving element DT at a first node N1.

The switching element ST may include an input terminal connected to thedata line DLj, the output terminal connected to the control terminal ofthe driving element DT through the first node N1, and a control terminalconnected to the scan line SLi.

The light emitting element ED may be connected to the driving element DTand a second power supply line PL2. For example, the light emittingelement ED may be connected to a first electrode E1 that is electricallyconnected to the driving element DT and a second electrode E2 that iselectrically connected to the second power supply line PL2. The lightemitting element ED can receive a second power supply voltage ELVSSthrough the second power supply line PL2. The second power supplyvoltage ELVSS may be lower than the first power supply voltage ELVDD.

A scan signal may be applied to the control terminal of the switchingelement ST through the scan line SLi, and the switching element ST canbe turned on in response to the scan signal. When it is turned-on, theswitching element ST may provide the data voltage that is receivedthrough the data line DLj to the first node N1.

The capacitance element C can charge an amount of charge correspondingto the difference between the data voltage provided to the first node N1and the first power supply voltage ELVDD and maintain the charge evenafter the switching element ST is turned off.

The driving element DT can be turned on according to the amount ofcharge charged in the capacitance element C. The turn-on time of thedriving element DT may be determined according to the amount of chargecharged in the capacitance element C. Current may flow through the lightemitting element ED when the driving element DT is turned on, and thelight emitting element ED emits light. The light emitting element ED mayemit light to generate an image.

The light emitting element ED may represent one or more microscale LEDelements. A micro scale LED element may have a length of severalnanometers to several hundreds of micrometers. It is noted that this ismerely an example, and the length of the microscale LED element is notlimited to the above numerical range.

FIG. 3 is a plan view illustrating the pixel shown in FIG. 2 including afirst electrode and a second electrode that are connected to the lightemitting element.

Referring to FIG. 3, the first electrode E1 includes a first extensionportion E1_1 extending in the first direction DR1 and a plurality offirst branch portions E1_2 extending from the first extension portionE1_1 in the second direction DR2 toward the second electrode E2.Although two first branch portions E1_2 are shown illustratively, thenumber of the first branch portions E1_2 is not limited thereto.

The second electrode E2 may include a second extension portion E2_1extending in the first direction DR1 and a plurality of second branchportions E2_2 extending from the second extension portion E2_1 in thesecond direction DR2 toward the first electrode E1. Although two secondbranch portions E2_2 are shown illustratively, the number of the secondbranch portions E2_2 is not limited thereto. The first branch portionsE1_2 and the second branch portions E2_2 may be disposed as being spacedapart from each other in a 1:1 alternation in the first direction DR1.

The pixel PX may include a plurality of first protruding electrodes PE1disposed on the first electrode E1 and a plurality of second protrudingelectrodes PE2 disposed on the second electrode E2. The first protrudingelectrodes PE1 may be disposed on the first branch portions E1_2 in oneor more rows corresponding to a number of rows of microscale LEDs.Similarly, the second protruding electrodes PE2 may be disposed on thesecond branch portions E2_2 in one or more rows corresponding to anumber of rows of the microscale LEDs. Although three rows of themicroscale LEDs, the first protruding electrodes PE1, and the secondprotruding electrodes PE2 are shown illustratively, the number of rowsof the microscale LEDs, the first protruding electrodes PE1, and thesecond protruding electrodes PE2 is not limited thereto.

The first protruding electrodes PE1 may be electrically connected to thefirst electrode E1 by contacting the first branch portions E1_2. Thefirst protruding electrodes PE1 may The second protruding electrodes PE2may be electrically connected to the second electrode E2 by contactingthe second branch portions E2_2.

The first protruding electrodes PE1 may be arranged in the seconddirection DR2. The first protruding electrodes PE1 may be evenly spacedin the second direction DR2. The second protruding electrodes PE2 may bearranged in the second direction DR2. The second protruding electrodesPE2 may be evenly spaced in the second direction DR2. A spatial gapbetween the adjacent first protruding electrodes PE1 and the adjacentsecond protruding electrodes PE2 in the second direction DR2 may besubstantially the same as a spatial gap between the adjacent firstbranch portions E1_2 and the adjacent second branch portions E2_2 in thesecond direction DR2.

The pixel PX may include a plurality of light emitting elements ED. Thelight emitting elements ED are disposed to overlap at least a portion ofthe first protruding electrodes PE1 and the second protruding electrodesPE2 and are electrically connected to the first protruding electrodesPE1 and the second protruding electrodes PE2. Both sides of each of thelight emitting elements ED may be respectively disposed on acorresponding pair of first and second protruding electrodes PE1 and PE2among the first and second protruding electrodes PE1 and PE2 included inthe pixel PX. The both sides of each of the light emitting elements EDmay contact the corresponding pair of first and second protrudingelectrodes PE1 and PE2, respectively.

The pixel PX may include a pixel area PA and a non-pixel area NPA aroundthe pixel area PA in a plan view. The light emitting elements ED may bedisposed in the pixel area PA.

FIG. 4 is a perspective view of one light emitting element ED shown inFIG. 3.

Although one light emitting element ED is illustratively shown in FIG.4, other light emitting elements ED included in the pixel PX will havethe same configuration as the light emitting element ED shown in FIG. 4.

Referring to FIG. 4, the light emitting element ED may have acylindrical shape extending in the first direction DR1. However, thepresent disclosure is not limited to this, and the light emittingelement ED may have a polygonal columnar shape extending in the firstdirection DR1. The light emitting element ED may be horizontally aligned(e.g., in the first direction DR1) and disposed on a pair of first andsecond protruding electrodes PE1 and PE2.

The light emitting element ED may include an n-type semiconductor layerNS, a p-type semiconductor layer PS, and an active layer AL that isdisposed between the n-type semiconductor layer NS and the p-typesemiconductor layer PS. The n-type semiconductor layer NS may be formedby doping an n-type dopant into a semiconductor layer. The p-typesemiconductor layer PS may be formed by doping a p-type dopant into asemiconductor layer. The semiconductor layer may include a semiconductormaterial. For example, the semiconductor layer may include galliumnitride (GaN), aluminum nitride (AlN), aluminum gallium nitride (AlGaN),indium gallium nitride (InGaN), indium nitride (InN), indium aluminumgallium nitride (InAlGaN), or aluminum indium nitride (AlInN), but thepresent disclosure is not limited thereto.

The n-type dopant may be silicon (Si), germanium (Ge), tin (Sn),selenium (Se), tellurium (Te), or a combination thereof, but the presentdisclosure is not limited thereto. The p-type dopant may be magnesium(Mg), zinc (Zn), calcium (Ca), strontium (Sr), barium (Ba), or acombination thereof, but the present disclosure is not limited thereto.

The active layer AL may be formed of at least one of a single quantumwell structure, a multiple quantum well structure, a quantum wirestructure, and a quantum dot structure. The active layer AL maycorrespond to an area where electrons injected through the n-typesemiconductor layer NS and holes injected through the p-typesemiconductor layer PS are recombined. The active layer AL may bedefined by a layer that emits light with energy determined by amaterial-specific energy band. The position of the active layer AL canbe varied depending on a type of the light emitting element ED.

The n-type semiconductor layer NS may be connected to one of the firstelectrode E1 and the second electrode E2. The p-type semiconductor layerPS may be connected to the other one of the first electrode E1 and thesecond electrode E2.

The length LT of the light emitting element ED may be between a fewnanometers and a few hundred micrometers. For example, the length LT ofthe light emitting element ED may be from 1 micrometer to 100micrometers.

FIG. 5 is a cross-sectional view taken along a line I-I′ of FIG. 3. FIG.6 is a cross-sectional view taken along a line II-II′ of FIG. 3.

Referring to FIGS. 2, 5, and 6, the pixel PX may include the drivingelement DT, the switching element ST, the first electrode E1, the secondelectrode E2, and the light emitting element ED. The driving element DT,the switching element ST, the first and second electrodes E1 and E2, andthe light emitting element ED may be disposed on a first base substrateBS1.

A second base substrate BS2 may face the first base substrate BS1. Thedriving element DT, the switching element ST, the first and secondelectrodes E1 and E2, and the light emitting element ED may be disposedbetween the first base substrate BS1 and the second base substrate BS2.Each of the first and second base substrates BS1 and BS2 may be asilicon substrate, a plastic substrate, a glass substrate, an insulatingfilm, or a laminated structure including one or more insulating layers.

According to one embodiment, the configuration of the driving element DTand the configuration of the switching element ST may be substantiallythe same. Hereinafter, the configuration of the driving element DT willbe mainly described, and the configuration of the switching element STwill be briefly described or omitted.

A buffer layer BFL may be disposed on the first base substrate BS1. Thebuffer layer BFL may include an inorganic material. The driving elementDT and the switching element ST may be disposed on the buffer layer BFL.

The driving element DT may include a first gate electrode GE1, a firstsource electrode SE1, a first drain electrode DE1, and a firstsemiconductor layer SM1. The switching element ST may include a secondgate electrode GE2, a second source electrode SE2, a second drainelectrode DE2, and a second semiconductor layer SM2.

The second gate electrode GE2, the second source electrode SE2, thesecond drain electrode DE2, and the second semiconductor layer SM2 ofthe switching element ST may respectively have the same structures asthe first gate electrode GE1, the first source electrode SE1, the drainelectrode DE1, and the first semiconductor layer SM1 driving element DT,and may be respectively disposed on the same layer.

The first semiconductor layer SM1 may be disposed on the buffer layerBFL. The first semiconductor layer SM1 may include an inorganicsemiconductor material such as amorphous silicon or poly silicon, or anorganic semiconductor material. Additionally, the first semiconductorlayer SM1 may include an oxide semiconductor material. Although notshown in FIG. 5, the first semiconductor layer SM1 may include a sourcearea, a drain area, and a channel area that is disposed between thesource area and the drain area.

A surface of the buffer layer BFL corresponding to the firstsemiconductor layer SM1 may be modified or treated before the firstsemiconductor layer SM1 is placed thereon. In this case, the firstsemiconductor layer SM1 may adhere to the buffer layer BFL strongercompared to a case in which the surface of the buffer layer BFL isunmodified or untreated surface. The buffer layer BFL may serve as abarrier layer for protecting a lower surface of the first semiconductorlayer SM1. In this case, the buffer layer BFL can prevent contaminationor moisture from penetrating into the first semiconductor layer SM1through the first base substrate BS1.

A first insulating layer INS1 may be disposed on the buffer layer BFLand cover the first semiconductor layer SM1. The first insulating layerINS1 may include an inorganic material. For example, the firstinsulating layer INS1 may include silicon nitride, silicon oxynitride,silicon oxide, titanium oxide, or aluminum oxide, but the presentdisclosure is not limited thereto.

The first gate electrode GE1 may be disposed on the first insulatinglayer INS1 overlapping the first semiconductor layer SM1. For example,the first gate electrode GE1 may overlap the channel area of the firstsemiconductor layer SM1. A second insulating layer INS2 may be disposedon the first insulating layer INS1 and cover the first gate electrodeGE1. The second insulating layer INS2 may include an inorganic material.

The capacitance element C (shown in FIG. 2) may include a first capelectrode (not shown) and a second cap electrode CPa. The first capelectrode may be branched off from the second gate electrode GE2, andthe second cap electrode CPa may be disposed on the second insulatinglayer INS2.

A third insulating layer INS3 may be disposed on the second insulatinglayer INS2 and cover the second cap electrode CPa. The third insulatinglayer INS3 may be referred to as an interlayer insulating layer. Thethird insulating layer INS3 may include an organic material and/or aninorganic material.

The first source electrode SE1 and the first drain electrode DE1 may bespaced apart from each other and disposed on the third insulating layerINS3. The first source electrode SE1 is connected to the source area ofthe first semiconductor layer SM1 through a first contact hole CH1 thatis defined by penetrating the first, second, and third insulating layersINS1, INS2 and INS3. The first drain electrode DE1 is connected to thedrain area of the first semiconductor layer SM1 through a second contacthole CH2 that is defined by penetrating the first, second, and thirdinsulating layers INS1, INS2 and INS3.

A fourth insulating layer INS4 may be disposed on the third insulatinglayer INS3 and cover the first source electrode SE1 and the first drainelectrode DEL The fourth insulating layer INS4 may include aplanarization film that provides a flat upper surface, and may includean organic material.

A first substrate SUB1 may be defined to include the first basesubstrate BS1, the buffer layer BFL, and the first to fourth insulatinglayers INS1 to INS4. A first partition wall layer BR1 and a secondpartition wall layer BR2 may be disposed on the first substrate SUB1 andspaced apart from each other. The first and second partition wall layersBR1 and BR2 may include an organic material.

The first electrode E1 may be disposed on the first substrate SUB1 andcover the first partition wall layer BR1. For example, the firstelectrode E1 may be disposed on the first partition wall layer BR1 andextend to be disposed on a portion of the first substrate SUB1 that isadjacent to the first partition wall layer BR1. Accordingly, the firstpartition wall layer BR1 may be disposed between the first substrateSUB1 and the first electrode E1, and the first electrode E1 may entirelycover the first partition wall layer BR1.

The second electrode E2 may be disposed on the first substrate SUB1 andcover the second partition wall layer BR2, and the second electrode E2may be spaced apart from the first electrode E1. For example, the secondelectrode E2 may be disposed on the second partition wall layer BR2 andextend to be disposed on a portion of the first substrate SUB1 that isadjacent to the second partition wall layer BR2. Accordingly, the secondpartition wall layer BR2 may be disposed between the first substrateSUB1 and the second electrode E2, and the second electrode E2 mayentirely cover the second partition wall layer BR2.

The first electrode E1 may be connected to the first drain electrode DE1through a third contact hole CH3 that is defined through the fourthinsulating layer INS4. Accordingly, the first electrode E1 may beelectrically connected to the driving element DT.

Each of the first and second electrodes E1 and E2 may have asingle-layer structure or a multi-layered structure. As an example ofthe single-layer structure, each of the first and second electrodes E1and E2 may include a reflective electrode. As an example of themulti-layered structure, each of the first and second electrodes E1 andE2 may include a reflective electrode and a transparent electrode thatis disposed on the reflective electrode.

The reflective electrode may include one or more of copper (Cu),aluminum (Al), and silver (Ag) and can reflect light. The transparentelectrode may include at least one of indium zinc oxide (IZO), indiumtin oxide (ITO), indium gallium oxide (IGO), indium gallium zinc oxide(IGZO), and a mixture/compound thereof and can transmit light.

The first protruding electrode PE1 may be disposed on the firstelectrode E1, and the second protruding electrode PE2 may be disposed onthe second electrode E2. As shown in FIG. 6, a plurality of firstprotruding electrodes PE1 may be disposed on the first electrode E1.Exemplarily, a cross-sectional view of the plurality of first protrudingelectrodes PE1 is shown in FIG. 6. In is understood that a plurality ofsecond protruding electrodes PE1 may be disposed on the second electrodeE2, and a cross-sectional view of the plurality of second protrudingelectrodes PE2 is substantially the same as that of the first protrudingelectrodes PE1.

The first protruding electrode PE1 may be electrically connected to thefirst electrode E1 by contacting the first electrode E1. The secondprotruding electrode PE2 may be electrically connected to the secondelectrode E2 by contacting the second electrode E2. The first and secondprotruding electrodes PE1 and PE2 may include a conductive material thatis different from that of the first and second electrodes E1 and E2.

The light emitting element ED may be disposed between the firstpartition wall layer BR1 and the second partition wall layer BR2. In thecross-sectional view of FIG. 5, a first side of the light emittingelement ED may be disposed on the first protruding electrode PE1, and asecond side of the light emitting element ED that is opposite to thefirst side may be disposed on the second protruding electrode PE2. Thefirst side of the light emitting element ED may contact an upper surfaceof the first protruding electrode PE1, the second side of the lightemitting element ED may contact an upper surface of the secondprotruding electrode PE2, the light emitting element ED may beelectrically connected to the first protruding electrode PE1 and thesecond protruding electrode PE2. The light emitting element ED may beelectrically connected to the first and second electrodes E1 and E2through the first and second protruding electrodes PE1 and PE2.

A first contact electrode CTE1 may be disposed on the first protrudingelectrode PE1 and may cover the first side of the light emitting elementED. Illustratively, the first contact electrode CTE1 is disposed on aportion of the first protruding electrode PE1 adjacent to the first sideof the light emitting element ED, but the present disclosure is notlimited thereto. For example, the first contact electrode CTE1 may bedisposed on the entirety of the first protruding electrode PE1. Thefirst contact electrode CTE1 may contact both of a side of the firstprotruding electrode PE1 that is close to the first side of the lightemitting element ED and the first side of the light emitting element ED.

A second contact electrode CTE2 may be disposed on the second protrudingelectrode PE2 and may cover the second side of the light emittingelement ED. Illustratively, the second contact electrode CTE2 isdisposed on a portion of the second protruding electrode PE2 adjacent tothe second side of the light emitting element ED, but the presentdisclosure is not limited thereto. For example, the second contactelectrode CTE2 may be disposed on the entirety of the second protrudingelectrode PE2. The second contact electrode CTE2 may contact both of aside of the second protruding electrode PE2 that is close to the secondside of the light emitting element ED and the second side of the lightemitting element ED.

The first and second contact electrodes CTE1 and CTE2 may include atransparent material. For example, the first and second contactelectrodes CTE1 and CTE2 may include at least one of indium zinc oxide(IZO), indium tin oxide (ITO), indium gallium oxide (IGO), indiumgallium zinc oxide (IGZO), and a mixture/compound thereof, but thepresent disclosure is not limited thereto.

In an embodiment where the light emitting element ED has a cylindricalshape as shown in FIG. 4, a side surface (or an outer circumferentialsurface) of the cylindrical shape may contact the first and secondprotruding electrodes PE1 and PE2, and the light emitting element ED maybe in line contact with the first and second protruding electrodes PE1and PE2. The line contact has a smaller contact area than a surfacecontact, and the contact resistance may increase due to the smallercontact area. Generally, the contact resistance can interfere with aflow of current.

However, the first and second contact electrodes CTE1 and CTE2 coverboth sides of the light emitting element ED and are disposed on thefirst and second protruding electrodes PE1 and PE2 so that the first andsecond contact electrodes CTE1 and CTE2 may increase a contact areabetween the light emitting element ED and are disposed on the first andsecond protruding electrodes PE1 and PE2. The increased contact areabetween the light emitting element ED and are disposed on the first andsecond protruding electrodes PE1 and PE2 may reduce the contactresistance between the light emitting element ED and the first andsecond protruding electrodes PE1 and PE2.

A fifth insulating layer INS5 may be disposed on the first substrateSUB1 and cover the first and second protruding electrodes PE1 and PE2,the light emitting element ED, and the first and second contactelectrodes CTE1 and CTE2. The fifth insulating layer INS5 may include aninorganic material.

A light conversion layer LCL and a black matrix BM may be disposed on asurface of the second base substrate BS2 that faces the first basesubstrate BS1. The light conversion layer LCL may be disposed in thepixel area PA, and the black matrix BM may be disposed in the non-pixelarea NPA. Some pixels PX may not include a light conversion layer LCL.FIG. 5 shows that the light conversion layer LCL and the black matrix BMare disposed in the same layer, but the present disclosure is notlimited thereto. For example, the light conversion layer LCL and theblack matrix BM may be disposed in different layers on the second basesubstrate BS2.

The light conversion layer LCL may include an emitter. For example, theemitter may convert a wavelength of a first color light that isgenerated by the light emitting element ED to emit a second color lighthaving a different color from the first color light. In someembodiments, the emitter may include one or more quantum dots. The firstcolor light may be a blue light, and the second color light may be a redlight or a green light.

A plurality of pixels PX including the light conversion layer LCL forconverting a blue light into a red light, a plurality of pixels PXincluding the light conversion layer LCL for converting a blue lightinto a green light, and a plurality of pixels PX not including the lightconversion layer LCL may be disposed on the display panel DP. Thus, red,blue, and green lights can be generated by the plurality of pixels PX.

However, the embodiment of the present disclosure is not limitedthereto. For example, the light conversion layer LCL can be replacedwith a color filter. In addition, the light conversion layer LCL may beomitted in some or all of the pixels PX. In this case, the lightemitting element ED may emit a blue light, a green light, or a redlight. The black matrix BM may prevent light leakage between theplurality of pixels.

A second substrate SUB2 may be defined to include the second basesubstrate BS2, the light conversion layer LCL, and the black matrix BM.

A sixth insulating layer INS6 may be disposed between the firstsubstrate SUB1 and the second substrate SUB2. The sixth insulating layerINS6 may be an optically clear adhesive film, or a pressure sensitiveadhesive film.

The second substrate SUB2 may be attached to the first substrate SUB1 bythe sixth insulating layer INS6. However, this is only an example, andin another embodiment of the present disclosure, the second substrateSUB2 and the sixth insulating layer INS6 may be omitted.

If the first and second protruding electrodes PE1 and PE2 are notdisposed on the first and second electrodes E1 and E2, the lightemitting elements ED may not be aligned in a predetermined directionwith respect to the first and second electrodes E1 and E2. In this case,unlike what is shown in FIG. 3, the light emitting elements ED may notbe aligned in the first direction DR1 with respect to the first andsecond electrodes E1 and E2 and/or may not be uniformly spaced from eachother in the second direction DR2.

However, in an embodiment of the present disclosure, the first andsecond protruding electrodes PE1 and PE2 are disposed on the first andsecond electrodes E1 and E2 as shown in FIG. 3, and the light emittingelements ED may be arranged in the first direction DR1 and evenly spacedapart from each other in the second direction DR2 with respect to thefirst and second protruding electrodes PE1 and PE2. Therefore, analignment degree of the light emitting elements ED can be improved. Themore specific reason why the alignment degree of the light emittingelements ED is improved will be described in detail below with respectto FIGS. 7 to 14.

FIGS. 7 to 14 are views for explaining a manufacturing method of adisplay device according to an embodiment of the present disclosure.

For convenience of explanation, FIGS. 7 to 11 are shown in a crosssectional view corresponding to FIG. 6, and FIGS. 12 and 14 are shown ina cross sectional view corresponding to FIG. 5. In addition, FIG. 13shows an enlarged view of the light emitting element ED disposed betweenthe first protruding electrode PE1 and the second protruding electrodePE2.

Below, illustratively, a manufacturing method for forming the firstprotruding electrodes PE1 will be described with reference to FIGS. 7 to11, but it is understood that the second protruding electrodes PE2 mayalso be formed substantially in the same method as the manufacturingmethod shown in FIGS. 7 to 11.

Referring to FIG. 7, a first conductive material CM1 may be provided onthe first substrate SUB1, and a second conductive material CM2 may beprovided on the first conductive material CM1. The first conductivematerial CM1 may be disposed on the first substrate SUB1 and cover thefirst partition wall layer BR1.

The first conductive material CM1 may be a material for forming thefirst electrode E1, and the second conductive material CM2 may be amaterial for forming the first protruding electrodes PE1. For example,the first conductive material CM1 may include a first metallic material,and the second conductive material CM2 may include a second metallicmaterial that is different from the first metallic material.

A first photoresist pattern PR1 may be provided on the second conductivematerial CM2. The first photoresist pattern PR1 may include aphotosensitive resin. The first photoresist pattern PR1 may include afirst portion L1 and a plurality of second portions L2 that is disposedon the first portion L1 and spaced from each other. In one embodiment,the first photoresist pattern PR1 may be formed by patterning a layer ora film of a uniform thickness and removing selective portions thereofexcept the plurality of second portions L2. In another embodiment, alayer or a film having a uniform thickness of the first portion L1 isprovided, and another layer of film having patterns of the plurality ofsecond portions L2 is provided on the first portion L1.

Referring to FIG. 8, a portion of the first and second conductivematerials CM1 and CM2 may be removed using the first photoresist patternPR1 as a mask. For example, a portion of the second conductive materialCM2 exposed by the first photoresist pattern PR1 may be first removed toexpose a portion of the first conductive material CM1 underneath, andthe portion of the first conductive material CM1 exposed by the firstphotoresist pattern PR1 may be removed.

The portion of the first conductive material CM1 exposed by the firstphotoresist pattern PR1 may be removed to form the first electrode E1.The first electrode E1 may correspond to a remaining portion of thefirst conductive material CM1. Although not shown in the drawing, thesecond electrode E2 may be similarly formed of another remaining portionof the first conductive material CM1.

According to one embodiment, a wet etching method may be used foretching the first and second conductive materials CM1 and CM2. Since thefirst conductive material CM1 and the second conductive material CM2 mayinclude different materials, a first etchant may be used to etch thefirst conductive material CM1, and a second etchant may be used toremove the second conductive material CM2. The first etchant may be adifferent etchant than the second etchant.

Referring to FIGS. 9 and 10, an upper portion of the first photoresistpattern PR1 may be removed by a thickness TH of the first portion L1.The thickness TH of the first portion L1 can be defined by a distancedifference between a lower surface and an upper surface of the firstportion L1 in a vertical direction. In addition, a portion of the firstphotoresist pattern PR1 disposed on a side surface of the firstpartition wall layer BR1 may also be removed. According to oneembodiment, a dry etching method using a fluorine-based gas may be usedfor removing the upper portion of the first photoresist pattern PR1.

Since the first photoresist pattern PR1 is removed by the thickness THof the first portion L1, portions of the first photoresist pattern PR1having the thickness TH may be removed, and portions of the firstphotoresist pattern PR1 having a thickness greater than the thickness THmay remain. As a result, as shown in FIG. 10, a second photoresistpattern PR2 defined by the remaining portions of the first photoresistpattern PR1 may be formed.

Referring to FIG. 11, portions of the second conductive material CM2exposed by the second photoresist pattern PR2 may be removed to form thefirst protruding electrodes PE1 on the first electrode E1. Although notshown in the drawing, the second protruding electrodes PE2 may also beformed on the second electrode E2 in the same method as the firstprotruding electrodes PE1. As described above, the second etchant may beused to etch the second conductive material CM2 to form the firstprotruding electrodes PE1.

If the first and second conductive materials CM1 and CM2 include thesame metal material, the same etchant may be used. In such a case, theportions of the second conductive material CM2 as well as portions ofthe first electrode E1 exposed by the second photoresist pattern PR2 maybe removed. But, in the present embodiment, the second conductivematerial CM2 includes a material that is different from the firstconductive material CM1, and the second etchant is used to selectivelyetch the second conductive material CM2, so that the second conductivematerial CM2 may be removed, and the first electrode E1 may remain asshown in FIG. 11.

As discussed above, the second photoresist pattern PR2 may be formed byremoving the upper portion of the first photoresist pattern PR1, so thesecond photoresist pattern PR2 corresponds to the remaining portion ofthe first photoresist pattern PR. In this case, the first photoresistpattern PR1 and the second photoresist pattern PR2 may be formed using asingle photoresist. Therefore, the single photoresist can be used toform the first and second electrodes E1 and E2 and the first and secondprotruding electrodes PE1 and PE2. This is advantageous over a processin which a first photoresist may be used for forming the first andsecond electrodes E1 and E2 and a second photoresist that is differentfrom the first photoresist may be used for forming the first and secondprotruding electrodes PE1 and PE2.

Referring to FIG. 12, the second photoresist pattern PR2 may be removed,and a solution LQ containing a light emitting element ED may be providedbetween the first partition wall layer BR1 and the second partition walllayer BR2. The solution LQ may be an ink or a paste. The solution LQ maybe a substance that can be vaporized at a room temperature or by heat.

Referring to FIG. 13, voltages of opposite polarities may be applied tothe first electrode E1 and the second electrode E2. A DC voltage or anAC voltage may be applied to the first electrode E1 and the secondelectrode E2. Voltages of opposite polarities may be applied to thefirst protruding electrode PE1 and the second protruding electrode PE2through the first electrode E1 and the second electrode E2. Accordingly,an electric field may be formed between the first protruding electrodePE1 and the second protruding electrode PE2.

Charges can be concentrated on the first protruding electrode PE1 andthe second protruding electrode PE2 that have a structure that protrudesfrom the first electrode E1 and the second electrode E2 as shown in FIG.12. Accordingly, a stronger electric field may be formed between thefirst protruding electrode PE1 and the second protruding electrode PE2.Bipolarity is induced in the light emitting element ED by the electricfield, and the light emitting element ED may be self-aligned to thefirst protruding electrode PE1 and the second protruding electrode PE2by a dielectrophoretic force.

The light emitting element ED can be easily aligned toward the firstprotruding electrode PE1 and the second protruding electrode PE2 by astronger electric field formed between the first protruding electrodePE1 and the second protruding electrode PE2. Accordingly, the pluralityof light emitting elements ED may be uniformly aligned in the firstdirection DR1 and uniformly spaced in the second direction DR2 to beconnected to the first protruding electrodes PE1 and the secondprotruding electrodes PE2. As a result, an alignment degree of the lightemitting elements ED can be improved.

Referring to FIG. 14, the first and second contact electrodes CTE1 andCTE2 may be provided on the light emitting element ED and the first andsecond protruding electrodes PE1 and PE2, respectively. The fifthinsulating layer INS5 may be provided on the first substrate SUB1 andcover the first and second protruding electrodes PE1 and PE2, the lightemitting element ED, and the first and second contact electrodes CTE1and CTE2. The display device DD may be manufactured by providing thesixth insulating layer INS6 on the fifth insulating layer INS5 andproviding the second substrate SUB2 on the sixth insulating layer INS6.

In relation to a display device and a method of manufacturing the sameaccording to an embodiment of the present disclosure, an alignmentdegree of light emitting elements of the display device may be improvedby aligning the light emitting elements to the first protrudingelectrodes that are disposed on the first electrode and the secondprotruding electrodes that are disposed on the second electrode.

Although the exemplary embodiments of the present disclosure have beendescribed, it is understood that the present disclosure should not belimited to these exemplary embodiments, but various changes andmodifications can be made by one ordinary skilled in the art within thespirit and scope of the present disclosure as hereinafter claimed.

What is claimed is:
 1. A display device comprising: a substrate; a firstelectrode disposed on the substrate; a second electrode disposed on thesubstrate and spaced apart from the first electrode; a plurality offirst protruding electrodes disposed on the first electrode; a pluralityof second protruding electrodes disposed on the second electrode; and aplurality of light emitting elements electrically connected to theplurality of first protruding electrodes and the plurality of secondprotruding electrodes.
 2. The display device of claim 1, furthercomprising: a first partition wall layer disposed between the substrateand the first electrode; and a second partition wall layer disposedbetween the substrate and the second electrode.
 3. The display device ofclaim 2, wherein the plurality of light emitting elements are disposedbetween the first partition wall layer and the second partition walllayer.
 4. The display device of claim 1, wherein the first electrodecomprises: a first extension portion extending in a first direction; anda plurality of first branch portions extending from the first extensionportion in a second direction intersecting the first direction, whereinthe second electrode comprises: a second extension portion extending inthe first direction; and a plurality of second branch portions extendingfrom the second extension portion in the second direction, wherein thefirst branch portions and the second branch portions are alternatelydisposed in the first direction.
 5. The display device of claim 4,wherein the plurality of first protruding electrodes are disposed on thefirst branch portions, and the plurality of second protruding electrodesare disposed on the second branch portions.
 6. The display device ofclaim 5, wherein the plurality of first protruding electrodes arearranged in the second direction and contact the first electrode.
 7. Thedisplay device of claim 6, wherein the plurality of first protrudingelectrodes are spaced uniformly in the second direction.
 8. The displaydevice of claim 5, wherein the plurality of second protruding electrodesare arranged in the second direction and contact the second electrode.9. The display device of claim 8, wherein the plurality of secondprotruding electrodes are spaced uniformly in the second direction. 10.The display device of claim 1, wherein both sides of each of theplurality of light emitting elements are respectively disposed on acorresponding pair of first and second protruding electrodes among theplurality of first protruding electrodes and the plurality of secondprotruding electrodes.
 11. The display device of claim 10, furthercomprising: a first contact electrode configured to cover a first sideof each of the plurality of light emitting elements and disposed on afirst protruding electrode of the corresponding pair of first and secondprotruding electrodes; and a second contact electrode configured tocover a second side of each of the plurality of light emitting elementsand disposed on a second protruding electrode of the corresponding pairof first and second protruding electrodes.
 12. The display device ofclaim 1, wherein the plurality of first protruding electrodes and theplurality of second protruding electrodes comprise a conductive materialthat is different from that of the first electrode and the secondelectrode.
 13. A manufacturing method of a display device, the methodcomprising: providing a first conductive material on a substrate;providing a second conductive material on the first conductive material;providing a first photoresist pattern comprising a first portion on thesecond conductive material and a plurality of second portions spacedapart from each other and disposed on the first portion; removingportions of the first and second conductive materials that are exposedby the first photoresist pattern to form a first electrode and a secondelectrode defined by remaining portions of the first conductivematerial; removing the first photoresist pattern from an upper portionof the first photoresist pattern by a thickness of the first portion toform a second photoresist pattern; removing portions of the secondconductive material that are exposed by the second photoresist patternto form a plurality of first protruding electrodes and a plurality ofsecond protruding electrodes; and electrically connecting a plurality oflight emitting elements to the plurality of first protruding electrodesand the plurality of second protruding electrodes.
 14. The method ofclaim 13, wherein the first electrode comprises: a first extensionportion extending in a first direction; and a plurality of first branchportions extending from the first extension portion in a seconddirection intersecting the first direction, wherein the second electrodecomprises: a second extension portion extending in the first direction;and a plurality of second branch portions extending from the secondextension portion in the second direction, wherein the first branchportions and the second branch portions are alternately disposed in thefirst direction.
 15. The method of claim 14, wherein the plurality offirst protruding electrodes are arranged in the second direction andcontact the first electrode, wherein the plurality of second protrudingelectrodes are arranged in the second direction and contact the secondelectrode.
 16. The method of claim 15, wherein the plurality of firstprotruding electrodes and the plurality of second protruding electrodesare spaced uniformly in the second direction.
 17. The method of claim13, further comprising: providing a first partition wall layer betweenthe substrate and the first electrode; and providing a second partitionwall layer between the substrate and the second electrode.
 18. Themethod of claim 17, wherein the electrically connecting of the pluralityof light emitting elements to the plurality of first protrudingelectrodes and the plurality of second protruding electrodes comprises:providing the plurality of light emitting elements between the firstpartition wall layer and the second partition wall layer; and applyingvoltages of opposite polarities to the first electrode and the secondelectrode to respectively dispose both sides of each of the plurality oflight emitting elements on a corresponding pair of first and secondprotruding electrodes among the plurality of first protruding electrodesand the protruding electrodes second protruding electrodes.
 19. Themethod of claim 18, further comprising: providing a first contactelectrode on a first protruding electrode of the corresponding pair offirst and second protruding electrodes; and providing a second contactelectrode on a second protruding electrode of the corresponding pair offirst and second protruding electrodes, wherein the first contactelectrode covers a first side of each of the plurality of light emittingelements and the second contact electrode covers a second side of eachof the plurality of light emitting elements.
 20. The method of claim 13,wherein the plurality of first protruding electrodes and the pluralityof second protruding electrodes comprise a conductive material that isdifferent from that of the first electrode and the second electrode.